It has be found that by stunning fish, the quality of the flesh of the fish is increased as death does not induce the creation of lactic acid in the flesh of the fish. Fish are stunned in a number of ways including the most basic method of hitting the fish with a bat to using more complex devices in which the fish are stunned using a pneumatically driven ram.
In most commercial operated fisheries more complex pneumatic rams are used as they are more efficient and less physically demanding on an operator. An example of a fish stunning device that uses a pneumatic ram is disclosed in International Patent Application No WO 01/97621.
When fish are harvested, they are located in a holding area and then pumped onto a table. The fish are grabbed by an operator and stunned usually using a pneumatically driven stunning device that is mounted to the table. A guide is used to guide the head of the fish into the stunning device to activate a trigger to cause the pneumatic ram to be extended and stun the fish. The fish is then withdrawn from the guide and passed further along the table for other operations such as bleeding.
A problem with this process is that often the fish are pumped onto the table in waves. A large number of fish are often located on the table at one time creating a backlog of fish. An operator that uses the fish stunning apparatus shown in WO 01/97621 must push the fish forwardly through the guide in order to stun the fish. The difficulty arises when the fish must be removed as the backlog often hinders or sometimes prevents the removal of the fish. Further, as there is a passageway that must be provided to allow fish to be passed further along the table, fish that have not been stunned can be passed through this passageway which is undesirable.